Faculty of Engineering and Technologyhttp://hdl.handle.net/123456789/15
Sun, 15 Sep 2019 21:58:51 GMT2019-09-15T21:58:51ZRemoval of heavy metals from aqueous medium and their impact on biological systemhttp://hdl.handle.net/123456789/868
Removal of heavy metals from aqueous medium and their impact on biological system
Choudhury, Tasrina Rabia
The presence of arsenic in groundwater has been recognized as a major problem for Bangladesh. Due to its high toxicity, even in low concentrations, it is a threat to human health. There are many techniques, which can be effectively applied to remove arsenic from water streams. Many technologies, including co precipitation with iron or alum, adsorption onto coagulated floc, ion-exchange resin, reverse osmosis, and membrane techniques, have been used to remove arsenic from aqueous solution. Moreover, these existing techniques are costly and they are not economically applicable in small community systems. Therefore, there is a need for developing cheap efficient methods for the removal of arsenic from drinking water. Adsorption techniques are simple and convenient and have the potential for regeneration and sludge free operation. The present work was performed to evaluate the use of duckweed (Lemna minor) and neembark (Azadirachta indica) without any pretreatment as alternate adsorbents for removing arsenic (III) from aqueous mediums. Moreover, the duckweed and neem bark were applied to the removal of arsenic from Bangladeshi As-contaminated drinking water samples in a single-step column operation.
For the removal of arsenic (III) using duckweed, various parameters were investigated that affect arsenic adsorption/desorption. Optimum arsenic (III) removal was obtained under the following conditions: initial As (III) concentration, 100 μg/L; duckweed amount, 3 g; average particle size, 0.595 mm; treatment flow rate, 1.67 mL/min; and pH, 5.5,respectively. The desorption efficiencies with 1M H2SO4 was observed 97.67%.
The adsorption characteristics of arsenic on neem bark, a low-cost natural adsorbent, were studied in the laboratory scale using real-life sample. Neem bark has tremendous potential as a remediation material for the removal of arsenic from groundwater. The present work investigates the possibility of the use of neem bark adsorption technology without any pretreatment in the removal of arsenic from aqueous media. Various conditions that affect the adsorption/desorption of arsenic are investigated. Adsorption column methods show the optimum removal of As (III) under the following conditions: initial arsenic concentration, 100 μg/L; neembark amount, 5 g; average particle size, 0.595 mm; treatment flow rate, 1.67 mL/min; and pH, 6.9; respectively. The desorption efficiencies with 1M of HCl after the treatment of groundwater were in the range of 79%.
The present study might provide new avenues to achieve the arsenic concentration for drinking water recommended by Bangladesh and the World Health Organization (WHO).
Tanning industries are one of the main economic activities in Bangladesh. It has been well documented that waste water discharged from tanneries without appropriate treatment that results in detrimental effects on the ecosystem. No eco-toxicity evaluation of any aquatic environment in Bangladesh has been conducted so far. There are various methods to remove Cr (III) and Cr (VI) including chemical precipitation, membrane process, ion exchange, liquid extraction and electrodialysis. These methods are non economical and have many disadvantages such as incomplete metal removal, high reagent and energy requirements, generation of toxic sludge or other waste products that require disposal or treatment. In contrast, the adsorption technique is one of the preferred methods for removal of chromium because of its efficiency and low cost. In this study, groundnut shell (Arachis hypogaea) and flax (Linum usitatissimum) have been used for Cr (III) and Cr (VI) removal from aqueous solution. The present study is intended to use of these locally available as conventional cheap materials as chromium adsorbents.
Adsorption and de-sorption of chromium (III) ions on groundnut shell from aqueous solutions have been studied using batch adsorption techniques with respect to the influence of contact time, pH, adsorbent dose, initial chromium concentration and particle size. Appropriate adsorption isotherm and kinetic parameters of chromium (III) adsorption on groundnut shell have also been determined. The results of this study showed that adsorption of chromium (III) by groundnut shell reached to equilibrium after 360 minutes of the experiment and after that a little change of chromium removal efficiency was observed. Maximum chromium removal (87.5 %) was obtained at pH 7.0. The adsorption of chromium by groundnut shell was found to decrease with the higher chromium concentrations in aqueous solutions, lower adsorbent doses and higher particle sizes. The desorption efficiencies with 0.5M KOH was observed 78%. It is observed that the adsorption of chromium (III) by groundnut shell follows Langmuir and Freundlich isotherm equation. The kinetic of the adsorption process follows the first order kinetics with a rate constant of 0.01min-1. The results indicate that groundnut shell can be employed as a low cost alternative to commercial adsorbent in the removal of chromium (III) from water and wastewater.
The removal of hexavalent chromium from aqueous solution using nutshell has been best suited for the treatment of real tannery effluents since Cr salt is used for tanning. Batch adsorption studies were carried out under varying experimental conditions of contact time, pH, adsorbent dose, initial chromium concentration and particle size. Appropriate adsorption isotherm and kinetics parameters of chromium (VI) adsorption on nutshell have also been determined. The adsorption followed first order rate expression. The equilibrium data fit well into Langmuir and Freundlich isotherms. Adsorption was maximum at an initial pH of 2.0. The desorption efficiencies with 1 M KOH was observed 87%. It is expected that the developed rate equation could likely be used for design and performance predictions of adsorption processes for treating chromate wastewaters.
Furthermore, adsorption of chromium (III) on flax from aqueous solutions has been studied using batch adsorption techniques. Batch adsorption studies were carried out under varying experimental conditions of contact time, pH, adsorbent dose, initial chromium concentration and particle size. Appropriate adsorption isotherm and kinetics parameters of chromium (III) adsorption on flax have also been determined. The results of this study showed that adsorption of chromium (III) by flax reached to equilibrium after 420 minutes. Maximum chromium removal (70 %) was obtained at pH 2.0. The adsorption of chromium by flax was found to decrease with the higher chromium concentrations in aqueous solutions, lower adsorbent doses and higher particle sizes. The desorption efficiencies with 0.5M KOH was observed 90%. It is observed that the adsorption of chromium (III) by flax fitted Langmuir and Freundlich isotherm equation. The kinetic of the adsorption process follows the first order kinetics with a rate constant of 0.01min-1. The results indicate that flax can be employed as a low cost adsorbent for the removal of chromium (III) from water and waste water.
A 60-day experiment was conducted to compare the accumulation and toxicological effects of arsenic in muscle, intestine and liver of shingi fish, H. fossilis (Bloch) after exposure to two concentrations (7.0 and 20.0 ppm) of arsenic trioxide. The highest/maximum level of accumulation of arsenic was observed in the liver whereas the lowest level of arsenic was found to accumulate in the muscle tissues at the end of exposure period. It is apparent from the study that the damage of the liver of test fish due to 15 days exposed period was less compared to the damage caused by 60 days exposure periods. The intensity of histological alterations was observed to increase gradually with the arsenic concentration and the exposure time.
This thesis submitted for the award of the degree of Doctor of Philosophy.
Sun, 05 Jun 2016 00:00:00 GMThttp://hdl.handle.net/123456789/8682016-06-05T00:00:00ZDevelopment of low frequency ferrite core materials using magnetite, a beach sand mineralhttp://hdl.handle.net/123456789/743
Development of low frequency ferrite core materials using magnetite, a beach sand mineral
Akhter, Shireen
Low frequency ferrite core materials of iron deficient Ni-Zn ferrites and iron excess Mn-Zn ferrites have been developed using cheap beach sand mineral magnetite (Fe3O4) as the basic ingredient as well as with the addition of low melting CuO, V2O5, Eu2O3 and In2O3 from the following compositions:
(i) Ni0.65Zn0.35Fe1.96O4+x[CuO, V2O5, Eu2O3, In2O3]
(ii) Mn0.451Zn0.484Fe2.065O4+x[CuO, V2O5, Eu2O3, In2O3]
A series of polycrystalline samples of mixed ferrites were prepared by standard ceramic method for systematic investigation of their physical, magnetic and electrical properties. Single phase cubic spinel structure of the prepared core materials has been confirmed by X-ray diffraction analysis. Physical properties such as; sintered density, lattice constant and microstructural properties of the materials have been measured. The magnetic and electrical properties of the core materials have been investigated by studying saturation magnetization, Curie temperature, initial magnetic permeability, normalized loss factor, dc resistivity and eddy current loss.
The addition of divalent V2O5 (melting point 700°C) and CuO (melting point (1026°C-1235°C) in the composition of iron deficient Ni-Zn ferrite enhances the chemical reactivity of the resulting mixture, facilitates the attainment of high degree of uniformity in the sintered body, increases the anion vacancy concentration and prohibit discontinuous grain growth which in turn enhances the density of the core materials. The lattice constant values of the ferrite system remain almost unaffected with the addition of V2O5 and CuO. The saturation magnetization, Curie temperature and initial magnetic permeability are enhanced appreciably with the addition of these two oxides. The minimum value of normalized loss factor, maximum value of dc resistivity and minimum value of eddy current loss are achieved for core samples containing 0.4 mol% and 1 mol% of V2O5 content respectively. For CuO addition, the minimum value of normalized loss factor, maximum value of dc resistivity and minimum value of eddy current loss are achieved for core samples containing 2 mol% of CuO content.
The addition of trivalent In2O3 (melting point 680°C) and Eu2O3 (melting point 623°C) in the composition of iron deficient Ni-Zn ferrite enhances the chemical reactivity of the resulting mixture, forms liquid phase on the grain surface of the ferrite and facilitates the attainment of high degree of uniformity in the sintered body which eventually promotes densification. The lattice constant values of the ferrite system increase almost linearly with the addition of these two oxides. The saturation magnetization, Curie temperature and initial magnetic permeability of the ferrite system decrease with the addition of In2O3. Whereas, all these parameters of the ferrite system increase markably with the addition of Eu2O3. However, the minimum value of normalized loss factor, the maximum value of dc resistivity and minimum value of eddy current loss of the ferrite system are achieved for core samples containing 3.5 mol% of In2O3 and 2 mol% of Eu2O3 respectively.
The addition of CuO and V2O5 in the composition of iron excess Mn-Zn ferrite enhances the density, however the lattice constant values of the ferrite system remain almost unaffected. The saturation magnetization of the ferrite system increases appreciably, whereas the Curie temperature decreases a little with the addition of CuO. The saturation magnetization and Curie temperature of the ferrite system increases markably with the addition of V2O5. However, the initial magnetic permeability of the ferrite system increases appreciably with the addition of CuO and V2O5. The minimum value of normalized loss factor, maximum value of dc resistivity and minimum value of eddy current loss are achieved for core samples containing 4 mol% of CuO. For V2O5 addition, the minimum value of normalized loss factor, maximum value of dc resistivity and minimum value of eddy current loss can be attained for core samples containing 0.6 mol% and 1 mol% of V2O5 content respectively.
The addition of Eu2O3 and In2O3 in the composition of iron excess Mn-Zn ferrite enhances the density as well as the lattice constant values of the ferrite system. The saturation magnetization and initial magnetic permeability of the ferrite system increases markably with the addition of these two oxides. There is no noticeable influence of Eu2O3 on the Curie temperature of the ferrite system. Whereas, the Curie temperature values of the ferrite system decrease with the increasing addition of In2O3.The minimum value of normalized loss factor, maximum value of dc resistivity and minimum value of eddy current loss can be achieved for core samples containing 2 mol% and 4 mol% of Eu2O3 content respectively. However the minimum value of normalized loss factor, maximum value of dc resistivitiy and minimum value of eddy current loss can be achieved for core sample containing 3.5 mol% of In2O3 addition. The possible applications of developed ferrite core materials are also discussed.
This thesis submitted to the department of Applied Physics, Electronics and Communication Engineering, university of Dhaka, in partial fulfillment of the requirement for the degree of Doctor of Philosophy.
Mon, 01 Jun 2015 00:00:00 GMThttp://hdl.handle.net/123456789/7432015-06-01T00:00:00ZStudy on the treatment of tannery solid wastes of Bangladesh for their potential utilisation.http://hdl.handle.net/123456789/739
Study on the treatment of tannery solid wastes of Bangladesh for their potential utilisation.
Deb, Amal Kanti
The tannery solid waste namely chrome shaving dust has been characterized and subjected to biochemical treatment using proteolytic enzyme and mild alkalis. In this study full chrome (chrome content 3.42 % and low chrome (chrome content 1.37 %) from cow wet blue leather have been used as raw materials for collagen protein extraction. MgO and CaO have been used for mild alkaline medium where trypsin, pepsin and proteinase K have been used as proteolytic enzymes. Several methods have been developed for the hydrolysis of chrome shaving dust after optimization of pH, types of alkalis and their dosages, variation of enzymes and their dosages and the amalgamation of enzymes. A three step hydrolysis process has been developed in all hydrolysis methods for the maximum recovery of collagen hydrolysate. The collagen hydrolysate has been extracted through vacuum filtration and preserved at 4 ºC in an incubator.
The prepared collagen hydrolysates by different methods have been analyzed for various physical and chemical parameters. MgO has been found to be better than CaO during hydrolysis since all the samples treated with MgO has given more protein yield. Trypsin enzyme has been found to be suitable for collagen hydrolysis compared to pepsin and proeinase K but the amalgamation of trypsin with proteinase K has given highest protein yield. The quality of collagen hydrolysate produced from the treatment of MgO is also better than that of CaO. Low chrome shaving dust has given more protein yield than that of full chrome shaving dust with the similar treatment. After complete hydrolysis, the chrome cake has been treated with sulfuric acid to separate the chromium present in chrome cake. The percentage of chrome recovery was 94.32% and 96.36% in samples 4 and 5 respectively.
All the samples have shown the characteristics protein peak during FTIR analysis. The collagen hydrolysates have been characterized by amide A and B bands, associated with NH stretching modes. The characteristics amide I, II and III bands have proved that the collagen was in hydrolyzed form. All collagen hydrolysates have been analyzed for the determination of chromium by atomic absorption spectrophotometer and trace amount of chromium (<4.5 ppm) was found in most of the samples while some samples contained below detection level of chromium (0.1 ppm). Ca and Mg content of collagen hydrolysate have also been determined by atomic absorption spectrophotometer and 1165 and 1033 ppm was found respectively. The protein content of the samples have been determined by BUCHI Kjeldhal instrument and found more protein yield in trypsin and MgO treated samples, amalgamated trypsin with proteinase K and MgO treated samples and low chrome shaving dust samples with similar treatment.
This biochemical method of producing collagen hydrolysate is environmentally friendly since there was no toxic chemical used in this method. Therefore, this approach of “waste to resource or wealth” will not only release the burden of disposal of tannery solid wastes but also produce valuable protein products which can be utilized in poultry feed, fertilizer and leather processing.
This thesis submitted at university of Dhaka in partial fulfillment of the requirements for the degree of Master of Philosophy (M.Phil.).
Thu, 28 May 2015 00:00:00 GMThttp://hdl.handle.net/123456789/7392015-05-28T00:00:00ZAnti-cancer and cytotoxic constituents from some Bangladeshi medicinal plantshttp://hdl.handle.net/123456789/723
Anti-cancer and cytotoxic constituents from some Bangladeshi medicinal plants
Kabir, Selina
This thesis describes the isolation and structure elucidation of secondary metabolites from
three plants namely Polyalthia simiarum Hook. F. and Thom.
(
Family- Annonaceae
)
,
Glochidion multiloculare
(
Roxb. ex Willd.)
Muell.-Arg. and Glochidion lanceolarium
(
Roxb.)
Voigt (
Family- Euphorbiaceae
)
as well as biological studies (
anti-cancer, antioxidant,
cytotoxic, antimicrobial, analgesic and antiinflamatory
)
of the extractives from these plants.
A total of twelve compounds were isolated of which one
(
PSB-001, 162
)
has been reported as
a new compound by us
(
Kabir et al., 2010)
. The structures of the isolated compounds were
elucidated mainly by high field NMR and mass spectroscopic techniques.
The petroleum ether extract of the stem bark of P. simiarum afforded four compounds viz.
PSB-001
(
2-Oxo-14,15-bisnor-3,11E-kolavadien-13-one, 162
)
, PSB-007
(
Kolavenic acid,
163
)
, PSB-004
(
16β-Hydroxycleroda-3,13(
14
)
Z-dien-15,16-olide, 164
)
and PSB-008
(
16Oxocleroda-3,13(
14)
E-dien-15-oic
acid, 165
)
. These four compounds are the first report of
their occurance from this respective plant. Among these compounds PSB-001
(
2-Oxo-14,15bisnor-3,11E-kolavadien-13-one,
162
)
represents the second report of the isolation of any 18carbon
containing bisnor-clerodane diterpenoid from nature and it appears to be new. The
petroleum ether soluble fraction of the methanol extract of the stem bark of Glochidion
multiloculare provided five comounds namely, GM-022
(
3-Epi-lupeol, 166
)
, GM-023
(
Lupeol, 167
)
, GM-029
(
Glochidone, 168
)
, GM-032
(
Glochidonol, 169
)
and GM-035
(
Glochidiol, 170
)
. On the other hand, chemical investigation of carbon tetrachloride soluble
fraction of the methanol extract of the stem bark of Glochidion lanceolarium yielded three
compounds GL-022
(
Epilupeol, 171
)
, GL-023
(
Glochidonol, 172
)
and GL-035
(
Glochidone,
173
)
.
The extractives of P. simiarum, G. multiloculare and G. lanceolarium were subjected to
assay for the anti-cancer activity against EAC tumor bearing mice. The antitumor activity of
the ethyl acetate
(
EA
)
extract of P. simiarum was determined against Ehrlich ascites
carcinoma
(
EAC
)
in mice at 25 mg/kg and 50 mg/kg body weight intraperitoneally.
Significant
(
p<0.001
)
increase of survival time by
(
25 ± 0.57 and 27 ± 0.40 days)
by the EA
extract treated tumor bearing mice was confirmed with respect to the control group
(
22 ± 0.12
days
)
. The antitumor activity of the extract/fractions
(
MEGM, PEFGM, CTFGM, CHFGM)of stem bark of G. multiloculare and also the extracts
(
MEGL, PEFGL, CTFGL
)
of G.
lanceolarium was determined against Ehrlich ascites carcinoma
(
EAC
)
in mice at 20 mg/kg
body weight intraperitoneally. Significant
(
p<0.001)
increase of survival time by 24 ± 0.12,
26 ± 0.40, 21 ± 0.12 and 27±0.42 days was observed by the extracts MEGM, PEFGM,
CTFGM and CHFGM treated tumor bearing mice with respect to the control group
(
20 ±
0.12 days
)
, whereas the increase of survival time by (
25 ± 0.32, 26 ± 0.10 and 23 ± 0.19 days)
by the extracts MEGL, PEFGL and CTFGL treated tumor bearing mice was also observed
with respect to the control group
(
20 ± 0.12 days)
. Treatment with different extracts of the
above mentioned plants decreased the intraperitonial tumor burden, thereby reducing the
tumor volume, tumor weight, viable tumor cell count and increased the life span of the tumor
bearing mice. Hematological studies revealed that the heamoglobin
(
Hb)
content was
decreased in EAC treated mice whereas restoration to close to normal levels was observed in
extract/fractions treated animals. There was a significant
(
p<0.001)
decrease in RBC and
increase in WBC counts in extract/fractions treated animals when compared to EAC affected
animals.
All the extractives and purified compounds of P. simiarum, G. multiloculare, and G.
lanceolarium were studied for free radical scavenging activity where tert-butyl-1hydroxytoluene
(
TBHT
)
was used as reference standard. In this study, the extracts MEGM,
MEGL, PEFGM, PEFGL and PEFPSB of the above mentioned plants showed highest free
radical scavenging activity with IC50 values 16.40, 18.32, 19.85, 20.29 and
21.5 μg/ml, respectively. The carbon tetrachloride soluble material
(
CTFGL
)
of G.
lanceolarium exhibited promising antioxidant activity having IC50 value of 22.24 μg/ml.
Compound PSB-004
(
164
)
and ethyl acetate fraction
(
EAFPSB
)
of P. simiarum revealed
potential antioxidant capacity with IC50 values of 23.5 and 24.5 μg/ml, respectively. In this
investigation, the CTFGM, CFFGM and AQFGM of P. simiarum showed moderate free
radical scavenging activity with IC50 values of 27.41, 32.30, and 38.17 μg/ml, respectively.
The crude extracts/fractions of the plants P. simiarum, G. multiloculare and G. lanceolarium
and two pure compounds
(
PSB-004 and PSB-007)
were subjected to brine shrimp lethality
bioassay for probable cytotoxic activity. The PEFPSB of P. simiarum exhibited highest
cytotoxicity with LC50 value of 1.91 μg/ml whereas EAFPSB of P. simiarum showed
promising activity with LC50 value of 3.65 μg/ml. The degree of lethality was directly
proportional to the concentration of extract ranging from the lowest concentration
(
0.78125μg/ml
)
to the highest concentration
(
400 μg/ml
)
. The positive control drug, vincristine sulfate
showed LC50 at 0.32 μg/ml. The LC50 values of PEFGM, CTFGM, CFFGM, MeEGM and
AQFGM of G. multiloculare were found to be 3.11, 4.96, 7.56, 9.23 and 16.32 μg/ml
)
,
respectively. The PEFGM exhibited significant mortality whereas CTFGM and CFFGM
showed moderate activity. Besides these, the LC50 values PEFGL, CTFGL, CFFGL, MeEGL
and AQFGL of G. lanceolarium were found to be 3.09, 6.70, 9.18, 14.24 and 17.68 μg/ml,
respectively. In this experiment, compound PSB-004
(
164
)
isolated from of P. simiarum
demonstrated strong cytotoxic activity with LC50 value of 2.29 μg/ml, whereas compound
PSB-007 (
163
)
of the same plant showed moderate activity with LC50 value of 8.84 μg/ml.
The extractives of the experimental three plants and two purified compounds
(
PSB-004 and
PSB-007 isolated from P. simiarum
)
were screened for their antimicrobial activity against a
number of test organism
(
both Gram-positive, Gram-negative and fungi
)
by the standardized
disc diffusion method. The results obtained were compared with that produced by the
standard antibiotic, Kanamycin. The petroleum ether
(
PEFPSB
)
and ethyl acetate
(
EAFPSB
)
soluble fractions of P. simiarum showed promising antibacterial activity with the average
zone of inhibition of 20-28 mm and 21-28 mm, respectively at 400 μg/disc. The pet-ether
soluble fraction revealed the highest activity against the growth of B. megaterium having the
zone of inhibition of 28 mm. In this study, the zones of inhibition produced by the extracts
CFFGM, PEFGM and CTFGM of G. multiloculare ranged from 9-12 mm, 8-10 mm and 7-9
mm, respectively. The carbon tetrachloride fraction
(
CTFGL
)
of G. lanceolarium was
screened against 12 test bacteria and 3 fungi. The zone of inhibition was 07-10 mm. The
fraction exhibited moderate activity against the test bacteria Salmonella typhi and Vibrio
parahemolyticus and Candida albicans, Aspergillus niger whereas, the petroleum ether
soluble fraction
(
PEFGL)
showed poor activity against the test organism. In case of pure
compounds, PSB-004
(
164
)
obtained from P. simiarum demonstrated moderate antimicrobial
activity against 12 test bacteria and 3 fungi, having the zone of inhibition 10-14 mm whereas,
PSB-007 (
163
)
showed poor activity against test bacteria and fungi.
The extracts/fractions of investigated plants were screened for probable analgesic activity
using Swiss albino mice as experimental animal. The EA and PE extracts of P. simiarum
showed analgesic activity in both tail flick and acetic acid induced methods at 50 and 100
mg/kg body weight. Among the extracts, the EA extract revealed a dose dependent analgesic
activity in the methods. Both the extractives of G. multiloculare
(
MEGM, PEFGM, CTFGMand CHFGM)
and G. lanceolarium
(
MEGL, PEFGL and CTFGL
)
at 100 mg/kg b.w.,
produced significant increase in pain threshold in tail flick method whereas significantly
reduced the writhing caused by acetic acid. All the tested extracts/fractions of investigated
plants were capable to exhibit moderate analgesic activity.
The extractives of P. simiarum, G. multiloculare and G. lanceolarium were subjected to
assay for the anti-inflamatory activity using Male Wister rats and Swiss albino mice as
experimental animal. The EA and PE extracts of P. simiarum, showed anti-inflammatory
activities at 50- and 100 mg/kg body weight. The EA extract reduced the paw edema
considerably
(
27.5% and 39.10% inhibition after 4h)
. In addition the extractives of G.
multiloculare
(
MEGM, PEFGM, CTFGM and CHFGM)
and G. lanceolarium
(
MEGL,
PEFGL and CTFGL
)
at the dose 100 mg/kg body weight showed anti-inflammatory activity.
The CTFGL of G. lanceolarium reduced the paw edema
(
0.85± 0.07, after 4h)
, when
compared to carrageenan induced control mice. Therefore, the extractives of the above
mentioned plants were found to exhibit moderate anti-inflammatory activity.
For the statistical validity of the results, all the tests were performed in triplicate or more and
the data have been presented as mean ± standard deviation.
This thesis submitted for the fulfillment of the requirements for the degree of Doctor of Philosophy in department of department of Applied Chemistry and Chemical Engineering
University of Dhaka.
Tue, 19 May 2015 00:00:00 GMThttp://hdl.handle.net/123456789/7232015-05-19T00:00:00Z